Decorative-stitching varying mechanism in zigzag sewing machines



July 13, 1965 DECORATIVE- TAMOTSU KOJIMA 3,194,196 STITCHING VARYING MECHANISM IN ZIGZAG SEWING MACHINES Filed Feb. 25, 1965 INVENTOR 7244a rsu AaJ/MA ATTORNEYS Jul 13, 1965 DECORATIVE- TAMOTSU KQJIMA 3,194,196 STITCHING VARYING MECHANISM IN Filed Feb. 25, I963 ZIGZAG SEWING MACHINES 2 Sheets-Sheet 2 INVENTOR 7214407190 AOJ/Mfl B m/M ATTORNEYS United States Patent 3,194,196 DECORATIVE-STITCHING VARYlNS MEfIHANiSM IN ZIGZAG SEWENG MACHINES Tamotsu Kojima, Kobe, Japan, assignor to Yoshio Doi, Osaka, Japan Filed Feb. 25, 1963, Ser. No. 260,473 Claims priority, application Japan, Feb. 26, 1962, 37/9,205 Claims. (Cl. 112-458) This invention relates to an improvement in zigzag sewing machines of the type having a mechanism for adjusting the amplitude of lateral oscillation of the needle bar, a mechanism for shifting the centerline of seam and a mechanism for reversing the direction of the material feed, and more particularly, this invention has for an Object to provide a new means adapted for use on such type of sewing machines, whereby a single motion produced by a pattern cam is changed into several composite motions by the switchover of a hand lever in the course of being transmitted to a zigzag-motion generating mechanism, to impart varied motions to the needle bar, so that decorative seams of complicated and varied patterns may be produced.

In order to accomplish the above-described function most easily and accurately, this invention provides a camfollower lever carrying at its base end a bifurcated arm member and a link member, the former being connected to a swingable plate member for adjusting the amplitude of zigzag motion and the latter to a movable arm piece for shifting the centerline of the needle vibration. By the switchover of a hand lever, the former two members are brought into and out of engagement with the latter two means, respectively, either simultaneously or separately.

With such arrangement, the single motion of the camfollower lever actuated by a pattern cam is transmitted to a zigzag-amplitude adjusting mechanism and a centerline shifting mechanism, either simultaneously or separately, so that the original motion of the lever can be changed into varied zigzag motions to actuate a zigzag-motion generating mechanism to impart various composite motions to the needle bar, whereupon the needle bar is rocked in various amplitudes to produce seams of varied patterns.

At the same time, a portion of the cam-controlled motion of the lever, to be transmitted to the arm piece for centerline shifting, is partly diverted to a shaft for feeddirection reversing to cause a feed-direction regulator to switch the direction of the material feed. This switchover of feed direction, coupled with varied lateral oscillations of the needle bar, serves to produce decorative seams of even more complicated and varied patterns with ease and accuracy.

The nature of this invention will be more clearly understood by refeercne to the accompanying drawings, illustrating unique elements and means employed to accomplish the function of the present invention. In the drawings:

FIG. 1 represents a front elevation, in vertical section, of a sewing machine provided with a new means of my invention for varying decorative seam.

FIG. 2 represents a plan view, in cross section, of the sewing machine shown in FIG. 1.

FIG. 3 represents a perspective view, showing the relationship between a feed-direction regulating mechanism and a cam-follower lever provided with a link member and a bifurcated arm member.

FIG. 4 represents a side view rial feeding.

FIG. 5 represents a plan view of a zigzag-motion generating mechanism.

FIG. 6 represents a plan view, showing the position of a cam-follower lever provided with a bifurcated arm and of a regulator for matea link member, the former being connected to a swingable plate means for zigzag-amplitude adjusting and the latter to an arm piece for centerline shifting.

FIG. 7 represents a plan view, showing the said bifurcated arm member in its different operative position.

All of the drawings illustrate only those elements and devices that are indispensable to my invention and the other component elements not related to the present invention were omitted from the drawings. The same reference numerals and characters refer to the same parts in the drawings.

The bracket-arm 1, hollow standard 2 and bed plate 3 are of the same shape and construction as those used in any conventional zigzag sewing machine and similarly, other component elements and means mounted inside those parts, such as a zigzag-motion generating mechanism in which a triangular cam 5 driven by the upper shaft 5 rocks an oscillator 8 having its one end pivotally secured by a pintle 7 to a movable arm 6 for centerline shifting, the rocking motion of the said oscillator 8 being transmitted to the needle bar 13 through a connecting rod 12 which is operatively connected with the oscillator 8 by means of a linking lever 10 carrying at its one end a roll er member 11 disposed in an arcuate groove 9 of the oscillator 3, a means for moving a shuttle on the under- 1 side of the bed plate 3 in time with the lateral rocking movement of the needle bar, and an amplitude adjusting means in which a cam shaft 14 driven by the upper shaft 4 carries thereon a pattern cam engaged by a cam follower lever 17 which is pivotally secured at its mid-point to the pivot joint 16, the said lever 17 being caused to swing about the pivot axis 16 reciprocatingly with the rotation of the said cam, thereby swinging an adjusting arm piece 19 through a bifurcated arm member provided at the base end of the lever 17, whereupon a roller member 11 carried by the linking lever 10 is caused to slide farther from or nearer to the pivot joint 7 so as to adjust the ampli tude of zigzag motion produced by the zigzag-motiongenerating mechanism, are the same as those in any conventional zigzag sewing machine.

Now, provided at the base end of the cam-follower lever 17 is a bifurcated arm 18 which accommodates in between its spaced ends a roller 20 carried by a movable arm 19 for amplitude adjusting, said arm member being pivotally secured to the machine frame at the joint 19. The bifurcated arm 18, having a long slot 21 which receives two screw members 22 and 22', is arranged to slide forward or backward. As shown in FIG. 6, however, the member 18 is normally held in backward position by the force of a spring 23 provided between the lever 17. and the member 18.

The bifurcated arm 18 also carries at its base end a pin 25 which, when a hand lever 24 pivoted on the camfollower lever 1'7 by means of their common pintle 16 was moved, is arranged to be pressed by the lever 24 so as to move the bifurcated arm 18 forward against the force of the spring 23 until, as shown in FIG. 7, the rear end of the slot 21 knocks against the rear screw member 22. In that position, in order to permit the arm 18 to, swing about the rear screw 22' as its fulcrum, the member 18 is provided with an arcuate slot 21' at: a position coincident with the position of the front screw member 22 transversely of the main slot 21.

Provided also on the cam-follower lever 17 at the opposite position of the bifurcated arm 18 in relation to the pivot axis '7 is a link member 26 which operates almost in the same fashion as the bifurcated arm 18, as described hereinafter. The link member 26 has its one end in constant engagement with a projection 29 provided at one end of a bell-crank lever 28 and has at its base portion a long slot 30 which accommodates therein two screws 31 and 31. The link member 26 is arranged to slide forward or backward, but it is normally held in backward position by the force of a spring 32 so that its tip engages constantly with the projection 29 provided on the bellcrank lever 28. The link member as is also provided at its other end a pin 33 which, when the hand lever 24 was moved, is pressed by the tip of the lever 24 so as to move the member 26 forward against the force of the spring 32 until the rear end of the slot 39 knocks against the rear screw 31. In that position, in order to permit the member 26 to swing about the rear screw 31' as its fulcrum, an arcuate slot 30 is provided on the member 26 at a position coincident with the position of the front screw 31 transversely of the main slot 3%. It will thus be known that the bifurcated arm 18 and the link member 26 resemble'each other in construction.

The other end of the bell-crank lever 28 is linked to a connecting rod 34 which carries at its end portion an elongated opening 35 accommodating therein a screw member 36 for connection with an arm piece 38 fixedly secured to an operating shaft 37 supported rotatably in the machine frame. The elongated opening 35 is branched off to form a cut-out portion in which the screw '36 is disposed and arranged to stay normally by means of a spring 40 which constantly pulls the tip of the connecting rod 34 to hold the screw as in that position.

Mounted loosely on the upper end of the said operating shaft 37 is a lever 41 which is arranged to swing upon the rotation of an externally-disposed handle 43 of a control cam 42 which is provided adjacent to the lever 41. The swinging motion of the lever 41 causes an elongated pin 44 carried at the tip of the lever 41 to press the connecting rod 34, causing the latter to swing out against the force of the spring 46), whereupon the cut-out 39 of the rod 34 is released from its engagement with the screw 36. As soon as the screw 36 entered into the elongated opening 35, the connecting rod 34 is released from its rigid connection to the operating shaft 37, so that the reciprocating motion of the connecting rod 34 imparted thereto by the pattern cam 15 through the cam-follower lever 17 may he raced away in the sliding movement of the screw 36 within the opening 35, with the operating shaft 37 remaining unaffected thereby. Consequently, the operating shaft 37 remains stationary despite the continued movement of the rod 34, as long as the screw 36 remains in the opening 35.

The operating shaft 37 carries at its lower end an elongated pin which is arranged to be engaged by a T-shaped member 49 constantly by the force of a spring 50 secured to the latter, the said T-shaped member being pivotally secured at the pivot joint 56 to a raised portion 48 of a regulator 47 which is cooperable with a forked lever 46 of the feeding mechanism to switch the direction of material feed. The T-shaped member 49 carries at its lower end another spring 51 which forces a pin 52 provided on one side of the T-shaped member d9 to engage with the raised portion 48 of the regulator 47 for feed-direction reversing, which perimts the regulator 47 to be biased in the prescribed direction on its fulcrum The forked rod 46 which is operatively connected with the regulator 47 will be held, in accordance with the position of the regulator shown in FIG. 3, in a position for forward feeding. A control member 54, is fixedly secured to one side of the regulator 47 to control the angle of inclination of the regulator 47 by means of an adjusting screw 55 rotatably supported in the machine frame and carrying at its external end a handle for hand operation.

Under such arrangements, when the hand lever 24 is moved leftward as shown in FIG. 2, the tip of the lever presses the pin 33 of the link member 26 to cause the latter to move forward against the force of the spring 32 until the rear end of the main slot 30 knocks against the rear screw member 31. At that time, as the front screw 31 will have been brought up to the crossing point of the main slot 39 and the branching arcuate slot 30, the cam-follower lever 17 swings, causing the front screw 31 to enter into the branching slot 3t), whereupon the linking member 26 is brought into a stationary position, but with its tip still engaging the projection 29 of the bell-crank lever 23. Thereupon, the swing motion of the cam-follower lever 17 is rendered ineffective.

The bifurcated arm 18 remains in a stationary position during that time, since the pin 25 of the member 18 is held away from the hand lever 24, and the two screws and 22' remain in the main slot 21 by the force of the spring 23 so as to hold the cam-follower lever 17 and the member 18 in a mutually fixed connection. In that position, the cam-controlled swing movement of the cam-follower lever 17 is transmitted in its original state to the swingable plate means 19 to zigzag-amplitude adjusting to cause the latter to swing, whereupon the roller 11 of the linking lever 10 connected to the swingable plate means 19 is caused to slide along the arcuate groove 9 of the oscillator member 8 farther from the axis 7. With the roller 11 shifted to that position, the oscillating motion of the oscillator 8 produced by the triangular cam 5 is transmitted, through the medium of the iinking lever 10 and the connecting rod 12, to the needle bar 13 to rock the latter so as to perform zigzag sewing. It will thus be known that, when the hand lever 24 is moved leftward, the motion of the cam-follower lever 17 is transmitted only to the oscillator 8 through the medium of the bifurcated arm 18, the swingable plate means 19 and the linking lever 10, and simply the rocking motion of the ocillator g is imparted to the needle bar.

When the hand lever 24 is moved rightward, the hand lever presses the pin 25 of the bifurcated member 13 to cause the latter to move forward against the force of the spring 23 until, as shown in FIG. 7, the rear end of the the main slot 21 knocks against the rear screw 22. At that time, since the front screw 22 will have been moved up to the crossing point of the main slot 21 and the branching slot 21, the cam-follower lever is swung, whereupon the front screw 22 enters into the branching slot 21., thereby bringing the bifurcated member 18 into a stationary position, with its spaced ends holding the roller 26 of the swingable plate means 19 therebetween. The swinging motion of the cam-follower lever 17 is thus rendered ineffective, thereby interrupting the roller member 11 of the linking lever 16 from sliding in the groove 9, quite contrary to the case when the hand lever 24 was moved leftward, whereupon the oscillating motion of the oscillator 8 actuated by the displacement of the said linking lever 10 is interrupted.

On the other hand, as the pin 33 of the link member 26 is held away from the tip of the hand lever 24, the link member 26 stays in its non-operative position and the two screws 31 and 31' remain in the main slot 30 by the force of the spring 32, thereby holding the cam-follower lever 17 and the link member 26 in a mutually fixed connection. In that position, the swinging movement of the cam-follower lever 17 is transmitted to the link member 2 6 in its original state, causing the tip of the lever 26 to press the projection 29 on the bell-crank lever 23, hence swinging the bell-crank lever 28 and the movable arm 6 about their common axis 27. Thereupon the pivot axis 7 at which the oscillator 8 is pivotally secured to the end portion of the movable arm 6, which naturally results in the displacement of the fulcrum'point on which the oscillator 8 pivots reciprocatingly upon the rotation of the triangular cam 5. This displacement is reflected in the shifting of the centerline of lateral oscillation of the neeedle bar, so that varied zigzag sewings can be effected. This is one of the unique features of the present invention.

Simultaneous with the above movement, the swinging motion of the cam-follower lever 17 is transmitted to the connecting rod 34 linked to the other end of the bell-crank lever 28 to move the rod 34, whereupon the screw 36 which has been engaging in the cut-out 39 of the rod 34 presses the arm piece 38 to cause the latter to swing, thereby imparting a rotatory motion to the operating shaft 37 and the elongated pin 45 secured thereto. Thereupon, the elongated pin 45 presses the upper end of the T-shaped member 49 to rotate the same on its pivot joint 56, so that the member 49 draws firmly the spring 56 secured at its one end to the lower end of the member 49 and at its other end to the regulator 47, thereby rotating the regulator 47 on its axis 53 against the force of the spring 51 so as to shift the position of the regulator 47 from forward feeding to backward feeding.

As the tip of the cam-follower lever 17 starts its return travel, moving from the high portion of the cam periphery to the low portion, the link member 26, the bell-crank lever 28, the connecting rod 34, the arm piece 38, the operating shaft 37, the elongated pin 45, the T-shaped mem ber 49 and the regulator 47 are acted upon to move in a manner contrary to that when the cam-follower lever 17 was making its forward travel on the cam periphery, so that all of them return to their original positions. Con sequently, the material feed which has once been shifted to the backward direction, is shifted again to the forward direction. This shifting of feed direction, superimposed on the zigzag motion described hereinbefore, permits decorative seams of more complicated and varied patterns to be produced. It will be understood from the above that, in order to produce decorative seams by the shifting of the centerline of the needle vibration, it is necessary that the screw 36 be received in the cutout 39 provided at the tip of the connecting rod 34.

In case, however, the shifting of feed direction is not required from the start for certain sewing operations or the switchover of feed direction is required to be interrupted during a sewing operation, the handle 43 is turned by hand to rotate the control cam 42 so as to rotate the lever 41 loosely mounted at the upper end of the operating shaft 37, whereupon the elongated pin 44 on the tip of the lever 41 is caused to press the side of the connecting rod 34 to move the same against the force of the spring 4i), thereby causing the screw 36 to disengage from the cut-out 39 and move into the elongated opening 35. With the screw 36 in that position, the swinging movement of the cam-follower lever 17 and hence the reciprocating movement of the connecting rod actuated thereby results only in the sliding movement of the screw 36 within the elongated opening 35, without any part of the reciprocating motion being transmitted to the operating shaft connected to the feed-direction reversing mechanism, so that the shaft 37 remains in its non-operative position. Thus, as long as the shaft 37 stays in that position, the switchover of feed direction does not take place.

Besides, when the hand lever 24 is positioned mid-way between its leftward position and rightward position as shown in FIG. 6, the hand lever 24 does not contact either the pin 25 of the bifurcated arm 18 or the pin 33 of the link member 26. Therefore, the members 18 and 26 will come to be drawn firmly by the springs 23 and 32, respectively, with the result that the screws 22 and 22' enter into the main slot 21 of the member 18 and the screws 31 and 31' into the main slot of the link member 26, thereby holding the both members in rigid con nection with the cam-follower lever 17. As a result, the swinging movement of the cam-follower lever 17 is transmitted through the bifucated arm 18 to a zigzag-motion generating mechanism in its original state in the same fashion as was already described when the hand lever 24 was moved leftward, to impart a zigzag-amplitude adjusting motion to the mechanism, while, at the same time, the swinging motion of the lever 17 is transmitted also to the zigzag-motion generating mechanism through the link member 26 in the same fashion as was already described when the hand lever was moved rightward, to impart two different motions, namely, centerline shifting motion and feed-direction reversing motion, to the-said mechanism.

The needle bar is thus caused by a combination of such motions to effect decorative stitchings of varied and complicated patterns. The advantages of the present invention can be best exploited in this operation.

As described hereinbefore, the present invention provides a unique means whereby, by positioning the hand lever 24 in three different positions, viz., leftward, rightward and central positions, the swinging motion of the camfollower lever 17 actuated by the pattern cam 15 is transmitted in some cases to the zigzag-motion generating mechanism in its original state to perform the ordinary zigzag sewing operation, and in other cases, the swinging motion is changed into varied motions in the course of being transmitted to the zigzag-motion generating mechanism, to enable the needle bar to effect unique zigzag sewing by the centerline shifting motion not produced by the triangular cam 5 or to effect a variety of zigzag sewings by means of the motion of the oscillator 8, superimposed on the centerline shifting motion, or to elfect zigzag sewings of even more complicated patterns by means of the feed-direction reversing motion, superimposed on either or both of the abovementioned motions.

Having thus described the nature of my invention, what I claim is:

1. A zigzag stitch sewing machine comprising a bed plate, work feeding means mounted in said bed plate, an arm overhanging said bed plate, a vertically reciprocating and horizontally oscillating needle bar carried by said arm, a drive shaft rotatably mounted in said arm, means connecting said drive shaft to said needle bar to reciprocate the same, means connecting said drive shaft and said feeding means for selectively driving said feeding means in forward or reverse direction, a cam driven by said drive shaft, needle bar oscillating means actuated by said cam, means to vary the amplitude and means to shift the field of oscillation of said needle bar, a second cam driven by said drive shaft, a lever pivotally mounted intermediate the length thereof, a cam follower on one end of said lever engaging said second cam, control means connecting the opposite end of said lever and said means to vary the amplitude of oscillation, a second control means connecting said lever and said means to shift the field of oscillation, and a third control means connecting said second control means and said feeding drive means, whereby upon rotation of said second cam said lever will operate to simultaneously and continuously vary the amplitude of oscillation, shift the field of oscillation and alternate the direction of feed.

2. A zigzag stitch sewing machine as defined in claim 1, in which a manually operable control handle is provided, means operable in one extreme position of said handle to render said first control means inoperative, and means operable in the opposite extreme position of said handle to render said second control means inoperative, said handle in an intermediate position permitting operation of both said first and second control means.

3. A zigzag stitch sewing machine as defined in claim 2, in which a second manually operable control handle is provided, and means connecting said second handle and said third control means for selectively rendering said third control means operative or inoperative. i

4. A zigzag stitch sewing machine is defined in claim 1, in which said first and second control means each include a plate, each plate having an elongated longitudinal slot therein, spaced pins received in each slot to slidably mount each plate on said lever, each plate having a transverse slot intersecting said longitudinal slot, spring means for yieldably holding each plate in position with said pins disposed at opposite sides of said transverse slots to provide a rigid connection between said plate-s and said lever to transmit movements of said lever to said first and second control means, movement of said plates to another position with one pin opposite each transverse slot permitting each plate to pivot about the other pin with said one pin moving in said transverse slots to provide a lost motion connection, thereby rendering said first and second control means inoperative by said lever.

5. A Zigzag stitch sewing machine as defined in claim 1 in Which said third control means includes a reciprocating link having an L-shaped slot in one end, one portion of said slot being disposed longitudinally of said link and the other portion being disposed transversely of said link, a pin received in said slot whereby with said pin disposed in said transverse portion, motion is transmitted from said link to said pin to render said third control means operative and with said pin disposed in said longitudinal portion a lost motion connection is provided to render said third control means inoperative.

References Cited by the Examiner UNITED STATES PATENTS 2,860,589 11/58 Sixt 112-158 3,108,556 10/63 Casas-Robert et al 112158 10 JORDAN FRANKLIN, Primary Examiner.

ROBERT V. SLOAN, Examiner. 

1. A ZIGZAG STITCH SEWING MACHINE COMPRISING A BED PLATE, WORK FEEDING MEANS MOUNTED IN SAID BED PLATE, AN ARM OVERHANGING SAID BED PLATE, A VERTICALLY RECIPROCATING AND HORIZONTALLY OSCILLATING NEEDLE BAR CARRIED BY SAID ARM, A DRIVE SHAFT ROTATABLY MOUNTED IN SAID ARM, MEANS CONNECTING SAID DRIVE SHAFT TO SAID NEEDLE BAR TO RECIPROCATE THE SAME, MEANS CONNECTING SAID DRIVE SHAFT AND SAID FEEDING MEANS FOR SELECTIVELY DRIVING SAID FEEDING MEANS IN FORWARD OR REVERSE DIRECTION, A CAM DRIVEN BY SAID DRIVE SHAFT, NEEDLE BAR OSCILLATING MEANS ACTUATED BY SAID CAM, MEANS TO VARY THE AMPLITUDE AND MEANS TO SHIFT THE FIELD OF OSCILLATION OF SAID NEEDLE BAR, A SECOND CAM DRIVEN BY SAID DRIVE SHAFT, A LEVER PIVOTALLY MOUNTED INTERMEDIATE THE LENGTH THEREOF, A CAM FOLLOWER ON ONE END OF SAID LEVER ENGAGING SAID SECOND CAM, CONTROL MEANS CONNECTING THE OPPOSITE END OF SAID LEVER AND SAID MEANS TO VARY THE AMPLITUDE OF OSCILLATION, A SECOND CONTROL MEANS CONNECTING SAID LEVER AND SAID MEANS TO SHIFT THE FIELD OF OSCILLATION, AND A THIRD CONTROL MEANS CONNECTING SAID SECOND CONTROL MEANS AND SAID FEEDING DRIVE MEANS, WHEREBY UPON ROTATION OF SAID SECOND CAM SAID LEVER WILL OPERATE TO SIMULTANEOUSLY AND CONTINUOUSLY VARY THE AMPLITUDE OF OSCILLATION, SHIFT THE FIELD OF OSCILLATION AND ALTERNATE THE DIRECTION OF FEED. 